Last week, Scotland's Labour leader Jim Murphy pledged he'll use the money raised from a mansion tax to pay for a 1,000 new nurses.

If Labour come to power in May the levy on properties worth more than £2million is set to hit London hardest.

And it brings back the question should the capital subsidise other parts of the UK?

Professor Tony Travers, director at the London School of Economics, Councillor Theo Blackwell, Camden council cabinet member for finance and technology, and Andy Silvester from the Tax Payers Alliance explain more.